SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '6d4cb48aa9a63b4941ea4b9213026118f31f1596952e82fe36e0c6afcd59a0e0' 
  AND token = 'W800iXTIQ7jAhji1a2dRDD6LeAzDwkw6iEydhqNfJKY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}